How to Install GNOME Themes in Ubuntu 12.04 LTS

Ubuntu 12.04 LTS uses Unity as the default Desktop Environment, which is based on Gnome 3. So Gnome 3 themes (window themes + GTK themes) works well in Unity as well as Gnome shell environment. You can manage themes in both environment using Gnome shell (of course some options will not be useful in Unity but there is a dedicated application for Unity Desktop – MyUnity).

The tutorial explains installing WIndow/GTK themes as well as about icon themes (although some icons/themes are available via PPA).